It is well known in the art to provide flexible pouches with a reclosable closure such as a zipper type, press to seal, or slide fastener closure. The flexible pouches are typically formed from a roll of continuous web of flexible film that is sealed along the side edges prior to the separation of the flexible film into individual separate pouches. The flexible film is preprinted with images and text describing the product to be contained therein. As such, it is important that the flexible film be accurately positioned with respect to the side seals that delineate the film into separate pouches.
Moreover, as the side seals extending across height of the pouch, the side seals pass through opposite ends of the closure. However, as the side seals typically utilize heat, pressure, ultrasonic, or any combination thereof, the seals must extend through or melt the plastic closure in order to bond the side edges of the pouch. As the closure has a thickness substantially more than the thickness of the walls of the pouch panel and it is required that the entire plastic fastener be heated in order to melt the plastic so as to fuse together and form a non-leaking side edge, substantial heat and time is required.
It has been previously known to provide the closure with a plurality of apertures prior to the connection with the flexible film. An example of such an apparatus is disclosed in U.S. Pat. No. 5,906,438 issued May 25, 1999, which is herein incorporated by reference in the entirety. The apertures are spaced so as to be along the side edges where the seals will made in order to reduce the amount of mass of the closure at the side seal edges so that the time required to form the seal, the size of the seal across the closure at the side edges, and the occurrences of faulty seals will be reduced.
With respect to FIG. 5, a previously known apparatus for installing a closure A to a flexible film B is illustrated at C. The flexible film B is unwound from a roll D and drawn into a pouch formation machine (not shown). A length of the closure A is wound around reel E and passes through a punch device F that forms the apertures G in the closure A. However, the main disadvantage of the previously known system is that the length of closure A is pulled through the punch device F and unwound from the reel E by the force of formation machine drawing the flexible material B. As such, the length of closure A is often placed under tension which stretches the closure A as it passes through punch device F. Upon release of the tension on the length of closure A the apertures G become smaller due to the contraction of the closure A. The reduction in size of the apertures G leads to various pouch defects, including the misalignment of the seals on the apertures.
Further, during the formation process the flexible film has a tendency to stretch which distorts the images preprinted on the flexible film. In addition, the stretching of the film can potentially cause the images on the film to become misaligned with the sealing and separation station. If the images are not properly aligned with the sealing station and the separation station, the separated pouches will be defective as the placement of the images are disfigured.
Accordingly, there exists a need for an apparatus capable of accurately aligning the continuous web of film so that the images and apertures are properly placed with respect to the side seals by relieving the tension in the flexible film.